“A Tale of a Burrowing Bug” and Cydnidae Pigmentation: a Case Report

Our Dermatology Online Case Report ““AA ttaleale ooff a bburrowingurrowing bug”bug” andand CydnidaeCydnidae ppigmentation:igmentation: A ccasease rreporteport Boothankad Chandregowda Sharathkumar, Seetharamapura Ramamurthy Radhika

Department of Dermatology, Venereology and Leprosy Kempegowda Institute of Medical Sciences Hospital and Research Centre, K R Road, Makalakuta Circle, V V Puram, Bangalore, India

Corresponding author: Dr. Seetharamapura Ramamurthy Radhika, E-mail: [email protected]

ABSTRACT

Exposure to insects or to their remains may range in severity from benign or barely noticeable to life-threatening conditions. The morphology of the cutaneous lesions may vary from several-millimeter asymptomatic noninflammatory lesions to large irritant dermatitis lesions, depending on the severity and the insects involved. A 3-year-old child presented with asymptomatic brownish patches on the bilateral soles persistent for a day. The mother gave a history of a visit to a temple and the onset of the lesions after the visit. A detailed examination reached the diagnosis of Cydnidae pigmentation. One of the benign conditions caused by the “burrowing bug” is Cydnidae pigmentation. As the lesions usually involve the acral areas, it has to be differentiated from other pigmented conditions, such as acral melanomas, lentigines, petechiae, and chemical/dye-induced pigmentations.

Key words: Cydnidae pigmentation; Chilocoris assmuthi; Burrowing bug

INTRODUCTION On clinical examination, multiple brown hyperpigmented macules and patches of varying sizes and shapes with Human cutaneous disorders may result due to multiple streaky pigmentation in several places were present on causes, such as nutritional deficiencies, toxins, bacterial the plantar aspect of both feet (more on the pressure- or fungal infections, exposure to insects, exposure to bearing sites). They were non-blanchable and non- chemicals, pollution, and medications. Insects cause tender, and the surrounding skin was normal (Fig. 1). varied patterns of dermatologic problems but, usually, these are inflammatory skin lesions [1]. Cydnidae On further investigation, the mother gave a history pigmentation is caused by Chilocoris assmuthi, which of visiting a nearby temple and walking barefoot as a belongs to the Cydnidae family, to the Hemiptera order, custom and of an appearance of these patches after the and to the Heteroptera suborder, which is known as visit. An examination of the mother revealed similar the burrowing bug, and which is uncommon in urban pigmented lesions on the bilateral soles. areas [2]. The mother and the child were informed of the benign CASE REPORT nature of the condition and were reassured.

An anxious, worried mother with a three-year-old son DISCUSSION entered our dermatology outpatient department during the monsoon season with complaints of a sudden Insects comprise the most diverse and numerous class appearance of brownish patches on the bilateral soles of the animal kingdom, hence human contact with of her son persistent for the last day. The lesions were them is unavoidable [1]. They may cause skin damage asymptomatic in nature. in humans through mouthparts, fangs, stingers, etc.

How to cite this article: Sharathkumar BC, Radhika SR. “A tale of a burrowing bug” and Cydnidae pigmentation: A case report. Our Dermatol Online. 2020;11(Supp. 3):24-26. Submission: 05.09.2019; Acceptance: 12.11.2019 DOI:10.7241/ourd.2020S3.8

In our case, the exogenous pigmentation caused by burrowing bugs was considered the most plausible diagnosis because of the similarities with the previously published cases [2,7,8]. The pigmentation due to these bugs is smaller (several millimeters) with streaky pigmentation and with tapering edges in several places [2]. Dermoscopy shows a cluster of oval to bizarre-shaped brown and shiny globules and clods with a superficial “stuck-on” appearance [3]. This may be differentiated from other causes of pigmentation, which may be due to other arthropods and coloring agents, by the involvement of a larger surface area. In cases of widespread lesions, one of the close differentials is petechiae secondary to dengue, which Figure 1: Multiple brownish hyperpigmented macules. is also prevalent in the monsoon season. Cydnidae pigmentation may be differentiated from lentigines by Hypersensitivity may develop against venoms or salivary the eruptive nature of the lesions and disappearance proteins. Insects may also act as vectors for many within several days [8]. infectious diseases [3]. Some of the skin disorders caused by arthropods include cimicosis (bed bug bite), pulicosis (flea infestation), pediculosis and Vagabond’s CONCLUSION disease (louse infestation), anaphylaxis (bee sting), This case of Cydnidae pigmentation is being published burns due to the formic acid produced by Formicidae for its rarity. According to the authors’ knowledge, this (ants), paederus dermatitis (blister beetle dermatitis), is the fourth case reported. Such pigmentation has lepidopterism (caterpillar dermatitis), myiasis (maggot to be differentiated from other causes, for instance, infestation), and Cydnidae pigmentation (due to exogenous causes of pigmentation, lentigines, acral Chilocoris). melanoma, dermatosis neglecta, and postinflammatory hyperpigmentation. The clue to the diagnosis of The Cydnidae are one of the most speciose families this pigmentation is a detailed history of brownish, within the Pentatomoidea superfamily and comprise sudden-onset macules of several millimeters with more than 750 species [4]. Its representatives are streaky or tapering edges usually occurring in the usually known under the common name of burrowing monsoon season and resolving spontaneously within bugs or burrower bugs due to their specific way of life, a week, as well as dermoscopy findings: a “stuck-on” as many of them live in the soil (soil diggers) and feed appearance with oval to bizarre-shaped brown shiny on roots. Some are above the ground as plant-feeders globules and clods. and may also feed on seeds. They produce an odorous substance from special glands found in the thorax of Consent adult insects, which is part of self-defense and is the cause of the pigmentation [5]. The pigmentation is The examination of the patient was conducted according to the not accompanied by any signs of inflammation, such as principles of the Declaration of Helsinki. color, dolor, rubor, tumor, or functio laesa. The common site of pigmentation is the acral area, although other REFERENCES sites may sometimes be involved. The pigmentation 1. Sarwar M. Skin disorders inﬂ icted through insect invertebrates along usually fades away with acetone but not with soap and with diagnosis and treating of cases. J Nanoscien Nanoengineer. water [3]. The secretion is a mixture of hydrocarbonates 2015;1: 233-40. and other derivatives, which functions as a repellent, 2. Malhotra AK, Lis JA, Ramam M. Cydnidae (burrowing bug) pigmentation: a novel arthropod dermatosis. JAMA may cause paralysis in the prey, and serves numerous Dermatol. 2015;151:232–3. other purposes, including danger signaling, helping 3. Sonthalia S. Dermoscopy of cydnidae pigmentation: a novel in attracting mates, and, interestingly, exhibiting disorder of pigmentation. Dermatol Pract Concept. 2019;9:228-9. 4. Lis J. Burrower bugs of the Old World - a catalogue (Hemiptera: antimicrobial activity [6]. These insects are usually Heteroptera: Cydnidae). Int J Invertebrat Taxon - Genus. considered harmless. 1999;10:165-249.

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